Assiolfor to the buntihg brass



A. F. DONALDSON: METHOD OF BROACHING ARTI CLES.

APPLICATION FILED AUG.20. 191?.

Patented Oct. M, i919.

' auensrus r. DONALDSON', or rorinno, onrognssfmnon 7130 Tan romaine nnnss' a BRONZE com any, or moni or), 'onxo, acom-omrion or 91110.. I

To all whom it may concern: 1 v,

Be it known that I, AUGUST-US F. DONALD- son, a citizen of the United States, and a resident of Toledo, inthe county of Lucas and State of Ohio have invented a certain 5 new and useful 'Miethod of Broaching-Ar tides; and I do hereby declare the following to be a .full, clear, and exact description of the invention, such as will enable others characters of reference marked thereon,

skilled inthe art to which it appertains to' make and use the same,\reference being bad to the accompanying drawings, and to the which form a part of this'specification.

Mv invention relates to breaches and. has

for its object to provide a means for breach-[- ing an object exteriorly. It also has for its a object to provide a means that will breach an object interiorly as well as exteriorly so as to produce a smooth interior surface. a

.It also has for its-object to provide a:- method of breaching objects exteriorly and interiorly.

My invention may be modified by those skilled in the art without departing from the spirit thereof. I shall describe hereinafter a construction containing my invention and,

one whereby the process maybe carried out in the use ofthe construction. The construction selected is illustrated in the accompanying drawings.

located in a socket 10 formed in the end of Figure 1 of the drawings is a side view of apart of a breaching machine, one of the broaches being shown in section. Fig. 2 is a top view of a stripper. plate for removing bushings from one of the breaches; Fig. 3 is a perspective view of an exterior; broac 1, Big. 1, is a bolster plate or bed of the broaching machine. 2 is a reciprocating plunger which is moved to and away from the bolster plate 1 by any suitable mecha-' nism. 3 is a holding member or sleeve for holding the exterior broach. It may be secured to the plunger 2 by'a suitable member .the' cutting operation and to break u Specification of Letters latentu Patented Oct. 14, 1919. Application m Au ust 20,1917. Serial in.- 187,204: 5

the sleeve 3 to preventjany lateral play of thebroach 7' within the sleeve. If desired,

, a compacting bead orring '11 may also be 4 inserted in the socket 10 and'so as to operateupon thearticle h t is broachedby the breach 7 t0 knead and compact the surface and give the article exterior polish.

The article to be broached exteriorly may be placed upon a suitable stem or support I so as to place the bushing substantially coaxial with the breach 7 and so that upon mo'vement of the brolch relative to the bushing the breach vwill cut the exterior surface of the bushing; [If a'bushin is to be broached it may placedon a man rel tight] fitting the bushing in order that the wal of the bushing willf 'be sustained while it is being 'op'erateduponlbyoutside breach. The mandrel may b made-slightly over-size as comparedtodthtlllinterior diameter of the bush ngin-ord ito allow forthe elasticity of themetal offtli e bushing, To facilitate the chipsthat are cutawa'y, the cuttin e ge of the broachhmay be providedwit cutting teeth 27 to fprevent continuity in the ring formation 0 the metal that is shaved or cut away from the article that is broached. The teeth may be formed by forming corrugated or saw she ed serrations. The serrations also provi ea means for extending the length of the cutting edgewhich reduces the force required to move the article through the breach .or to move the breach over the article. In the broach shown, the serrations are saw tooth shaped and the points of the teeth terminate' ridges 28 that extend radially from the center-- of the breach which give strength to the'teeth that they would not have if thepoints formed the intersection of inclined radial y extending planes and the exterior cone surface shown in Fig. 3 of'the draw'ing r r The interior diameter of the broach varies it is made sufficiently less than the diameter of the bushing or the artieleto be hroachcd to insure the maiiitenance of the edge be- ,neath the scale or crust-like surface formed on the article inthe casting thereof. For

breaching a bronze article, the breach should have a diameter of .035 of an inch less than the article in the rough in order that the broach may maintain its position beneath the or crust-like surface during the" breaching operation. This istrue of es abput-l .mchin diameter. If howeverg 'thatincreasein diameter successivel the uncle to be produced is to have a greater diameter, the difi'erence between the article -in the rough castin and the inner diameter of the breach shou d be greater on account 1 of the variability of the diameter of the 3' article at'difi'erent w h-ile in the rough.

. A stripper plate 12 may be located in the points along the article socket 10v or it may be located in a recess formed'in the inclosed beaded ring 11. The" stripper plate is provided with an opening is to receive-the articles broached. Itforms two spring pressedsemi-rings, the diameter of the opening being less than the diameter iii the articles broached. It is .formedb cutting the plate through" at one, side sue :theopposite side such as at The edge 6f the open as at 14 and reducing its cross section on of the stripper late moreover is bevele so as to permitt stripper plate to pass over the bushing and cause the stripper plate to spread and when the article has passedthrough the stripperiplate,

willslip beneath the article and engages 1t.

.. when a bushing is to be broached both lexteriorly andintcriorly, it may be placed l i -,so as to hold it withinthe sleeve 3. The

article may then be pushed by any suitable means through the opening 6.

' on the end of the interior broach such as upon the pilot 16 of the breach 17. The

broach' 17 may be bolted or secured to the bolster plate onto the bed 1 of the machine in any suitable way: When the plunger 2 descends, the broach-7 will engage the bush' ing near its outer edge and push the bushing over the broach 17 until the bushin is brought to a stop by means of a she der 18 formed on the breach 17 whereupon the broach 7 will operate to breach the bushing exteriorly and until the bushing passes through the stripper plate 12 into the sleeve 3.

The broach 17 may be used with any suitable female breach when it is desired to i breach the interior and the exterior of the bushings in one operation of the ram of the unch press. It has, however, been found 1n practice that the compressing action of the male broach will, under such conditions, produce irregular surfaces on the interior of the, bushing. The best results are obtained when the breaches operate in succession on the bushing. This will revent operation of either of the breaches w an the other lbroach is cutting or compacting the surface and thus the bushing will be operated upon when it is uniformly compressedor stretched, that is, when its wall is sustained against the action of one or the other of the broaches.

In the form of interior breach shown in ridge 22 that is away from t The broach 17 is also provided with a shank from 'the pilot 16. A bead 2 1 is located be ow the cutting ridges 19 whichoperates to knead ceding cutting ridge 19. his is followed with the ridge 22 which has a diameter that bushing has been stopped by theshoulder 18" located in the lower end of the shank 24c and the breach? has performed its operation n:

3 bushing is caught by the stri per plate 12 the exterior surface of the b i and the drawing, the 'broachis provided with outtmg-ndges -lil having cuttingcdges 20 the interior surface of the bushing. The bead 21 is of a diameter lar r than the pre- I on thereturn movement of-t e plunger 2, 9

the bushing is cut by the edge 23 of the ridge 22 and'is agam operated upon by the bead 21 and to a very slight extent by-the surface of the-lowermost ridge19sinoe the diameter of" the finished bushing is substan I tially the same-as the diameter of the lower-z most cutting ridge 19.- To form a bushing having substantially 1 inch interior diameter when finished, the uppermost ridge 19 may be made about of an inch undersize. The bead 21 maybe made .0041. of an inch oversize the cutting ridge 22. may be made .003 of an inch oversize and the shank 2t may be .002 of an inch oversize. These'dimansions of course will be varied according to the composition. of the metal, the thicknes of the wall of the bushing and accord ing to the diameter of the bushing '00 be formed. The number of cutting ridges and beads may also be variedaccording formed by the broaches.

to the conditions existing in the bushing that is Uiiless the wall of the bushing is exceed ingly thick, it has been found that the hornpressing produced by the cutting actioil of the breach 7 while the bushing is on the shank 24, that notwithstanding the fact that the shank 2 1 is oversize yet a watered silk appearance of the bushing is s0metimes produced on the interior of the bushing but without causing any mechanical defects in the bushing if removed from the shank without being passed again over the cutting ridges and beads. ever is removed by the return of the bushing a it passes over the cutting edge 23 of the ridge 22 which is about .001 of an inch larger than the shank 24. The bushing is again acted upon: by the bead 21 to form a 1 fin?" g it-am,

This appearance how-.

ame

compacted layer beneath the "s' 1 this way operates the shine as two'heeds en a breach that is pushed straight through the :bushing Without the return of the breech.

I claim:

1;The process of groducing bearings which ccnsists in broac ing the interior of the bushing then breaching the exterior of the bushing and then again breaching the interior ofthe bushing.

the bushing, then hroeching the exterior of i the 'bushin While the bushing is retained in In testimony whereof, I have hereunto 2. The method 01E *blOiMEhiIlg bushings; which cpnsists in breaching the interior of signed m name to this specification. KUG'USTUS F. DONALDSON. 

